Platform Power Management

To improve device battery life, Android can affect the device state by
monitoring device use and wakefulness. The platform can enter a state of
sleep to pause activities from running while the device is unused.

Doze

Doze extends battery life by deferring application background CPU and
network activity when a device is unused for long periods.

Idle devices in Doze periodically enter a maintenance window, during which
apps can complete pending work (syncs, jobs, etc.). Doze then resumes
sleep for a longer period of time, followed by another maintenance window. The
platform continues the Doze sleep/maintenance sequence, increasing the length of
idle each time, until a maximum of a few hours of sleep time is reached. At all
times, a device in Doze remains aware of motion and immediately leaves Doze
if motion is detected.

Android 7.0 and higher extends Doze to trigger a lighter set of optimizations
every time a user turns off the device screen, even when the user continues to
move around, enabling longer lasting battery life.

Critical system services are generally set up by device manufacturers to be
exempt from Doze. Users can also exempt specific apps from Doze via the
Settings menu. However, exempting apps may cause battery drain on the device.
By default, Doze is disabled in AOSP; for
details on enabling Doze, see Integrating Doze.

Doze requirements

Doze support requires the device has a cloud messaging service, such as
Firebase
Cloud Messaging (FCM). External triggers events, such as cloud messages,
can temporarily wake apps to do work while the device remains in Doze mode.

Full Doze support also requires a
Significant
Motion Detector (SMD) on the device; however, the lightweight Doze mode in
Android 7.0 and higher does not require an SMD. If Doze is enabled on a device
that:

Has an SMD, full Doze optimizations occur (includes lightweight
optimizations).

Does not have an SMD, only the lightweight Doze optimizations occur.

Doze lifecycle

Doze begins when the platform detects the device is idle and
ends when one or more exit criteria activities occur.

Detection

During Doze

Exit

The platform detects a device is idle when:

Device is stationary (using significant motion detector).

Device screen is off for some amount of time.

Doze mode does not engage while a battery-powered device is plugged into a power charger.

The platform attempts to keep the system in a sleep state, periodically
resuming normal operations during a maintenance window then returning the device
to sleep for longer repeating periods. During sleep, the following
restrictions are active:

Apps not allowed network access.

App wakelocks ignored.

Alarms deferred. Excludes alarm clock alarms and alarms set using
setAndAllowWhileIdle() (limited to 1 per 15 minutes per app while
in Doze). This exemption is intended for apps (such as Calendar) that must show
event reminder notifications.

Wi-Fi scans not performed.

SyncAdapter syncs and JobScheduler jobs deferred
until the next maintenance window.

Apps receiving SMS and MMS messages are put on a temporary whitelist so
they can complete their processing.

The platform exits the device from Doze when it detects:

User interaction with device.

Device movement.

Device screen turns on.

Imminent AlarmClock alarm.

Notifications do not cause the device to exit from Doze.

Android 7.0 and higher extends Doze by enabling a lightweight sleep mode
during screen off, before the device is idle.

Interaction with App Standby

Time spent in Doze does not count towards App Standby.

While the device is in Doze, idle applications are allowed to perform normal
operations at least once a day.

Integrating Doze

When Doze is enabled, devices that support
SENSOR_TYPE_SIGNIFICANT_MOTION
perform full Doze optimizations (including lightweight optimizations);
devices without an SMD perform only lightweight Doze optimizations. Android
automatically selects the appropriate Doze optimizations and no vendor
configuration is necessary.

To enable Doze for a device:

Confirm the device has a cloud messaging service installed.

In the device overlay config file
overlay/frameworks/base/core/res/res/values/config.xml, set
config_enableAutoPowerModes to true: